All Questions
Tagged with transformer three-phase
84 questions
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Three phase rectifier output current
I´m designing a three phase power transformer, and i´m having troubles with the choosing the current value. After the transformer, goes through a three phase bridge rectifier ( full wave and not ...
- 155
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1
answer
56
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Single transformer unit with identical groups of Dz windings around the same core
Background
I’m working with a three phase transformer with a 480v Delta primary and a 240v Zig Zag secondary. However, it actually contains two primaries (combined in parallel) and two secondaries ...
- 11
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votes
2
answers
356
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Power transformer design calculations
I´m currently designing power transformers in a pretty basic way, using AWG tables for the section of the copper wire, and not knowing what are the real losses, just overdesigning.
Three phase ...
- 155
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3
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288
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Need to make 380V and 415V 3-phase motors work with 480V 3-phase power supply. Will a 480V->400V autotransformer cut it?
I will have multiple 415V and 380V motors to power with a 480V/3-phase supply due to an international supply chain and tight budget. I would like to know if the solution to my issue is as simple as ...
- 417
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1
answer
121
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Meaning of this power system line diagram symbol
Please explain to me what this symbol means, in single line diagram?
Source of image: My project diagram.
Here is another example I found:
Here is a magnified part, showing the symbol:
Source of ...
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83
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Three-phase transformer with only two cores?
I'm an electrician. My foreman said the transformer we're having installed is three-phase, but only has two cores. The cores are placed in separate compartments, with a divider between them. I've ...
- 101
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1
answer
71
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How to find the "voltage across each winding" for different delta and star connections in a three phase transformer system? [closed]
I have got results from testing with delta/delta, delta/star, star/delta and star/star configurations. I've got the line and phase voltages for each configuration for both primary and secondary coils.
...
- 13
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2
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112
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How is my isolation transformer not short circuited?
I received a 3 phase 240 to 208 isolation transformer, and I am unsure how the current configuration (as it was shipped to me) would not cause a short circuit. When I do an ohms reading on the high ...
- 11
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2
answers
94
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What is the best way to convert 3ph 380VAC to 3ph 0V >> 450VAC in range of 800 kW?
I have a company that makes servo AC voltage regulators and some other transformer-based products, and today some of my customers asked me to give him a quotation for an 800 kW Variac, the biggest one ...
2
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2
answers
230
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Could a device connected to one MCB/phase affect a device on another MCB/phase?
I have a 3-phase 230V residential supply. It's divided among 3 groups of MCBs all powering single phase devices.
The problem I'm having is that whenever the air conditioning (single phase) turns on ...
- 167
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2
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199
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How to test three-phase transformer's rated kVA
I work as an electrical quality engineer at the borders. I test electrical transformers, and the government takes tax money according to the capacity rated kVA of the electric transformer.
We ...
- 11
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3
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811
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Can I wire a three phase, nine wire dual voltage motor for single phase 220V?
I have a 5hp nine wire, three phase dual voltage (low / high) motor and I need it to run on 220V single phase for an air compressor.
Please help - I've had several "electricians" say they ...
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1
answer
305
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Three Phase Transformer Design
I design single phase transformers, around 400W - 8000W, but now im lost because i have to design a three phase transformer ( delta - delta connection ).
I searched, trying to find a page that can ...
- 155
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229
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How much leakage current is too much in a transformer?
I have a 3-phase transformer with 3 primary windings and 3 pairs of secondary windings. I'm trying to test the isolation between the secondary winding pairs.
To do this I shorted A1, B1, C1 and A2, B2,...
- 151
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1
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How to wire a 480 V AC to 380 V AC transformer?
I have to install a reflow oven which needs 3-phase 380 V AC to power on.
There is a transformer (as the picture shows) that came with the oven. I assume that the black wire is the "hot" ...
- 13
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4
answers
2k
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Can I get a neutral from a three-phase supply using a step-down transformer (415 V to 230 V)?
I have a three-phase supply voltage, between them is 415 V.
Can I connect a 415/230 V step-down transformer between any two phases and use the output of the transformer as phase and neutral?
Or ...
3
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3
answers
3k
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How do utility lines wire transformers to go from 3-phase power to residential split phase?
I'm trying to understand how power distribution lines go from 3-phase to single-phase and haven't been able to find a concrete explanation.
I understand that power companies transmit with 3-phase ...
- 33
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1
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318
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380 V to 220 V three-phase
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I purchased a heat press that was supposed to be 220 V, 3-phase, but 380 V showed up. It is 12 kW, 32 A, no moving parts or motors. It came from overseas so ...
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1
answer
176
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What is the power rating for a 3-phase transformer based on the secondary voltage?
We want to install equipment on a 60 Hz, 400 V Delta system. The equipment is not suitable to work on a 400 V Delta system, therefore we can place a transformer to create a star configuration and are ...
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1
answer
103
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How would a step-down transformer's secondary line-to-line current change when adding 3-phase motor loads?
I currently have a 45 kVA, 600 to 480 V, delta to wye step-down transformer designed into my system.
I've done the calculation of 45 kVA / 480 V · √3 to roughly get 54.13 A.
Would this current value ...
- 83
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126
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Modeling three phase load for EV charger
When designing a power system to supply EV charging stations, are the stations modeled as delta loads or wye loads? Slightly off topic but is it standard practice to assume that three phase loads are ...
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2
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399
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How do I connect a three phase transformer with three center taps?
I have a three phase step down transformer with three center taps like shown below:
How can I connect it to get the 90 V three phase lines or the 45 V three phase lines at a time for circuits that ...
- 366
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1
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78
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Will the phase shift be mutual if one phase is stepped down through isolated transformer and added to another phase?
i came across this concept of creating phase shift ( lagging and leading conditions) by adding a stepped down line voltage in series with a different phase voltage. I physically verified the concept ...
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257
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neutral to ground voltage in ungrounded Y connection
A 2 MVA transformer 13.8kV Delta / 400V Y ungrounded neutral the voltage at the LV side of the Main circuit breaker terminals between the neutral and ground is 70 Volts, so, the technician isolated ...
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2
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1k
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Standard practice for earth connection when we use transformers
We bought the below device (two transformers inside a housing) from a local manufacturer and the connections was as noted in the schematic. We don't want to use the neutral from the utility. That's ...
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1
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114
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Parallel Operation of Transformers [closed]
Can we connect Dz1 and Dz11 in parallel, in the case of transformer banks?
In the transformers industry, under the standards like IEC 60076 and IEEE C57.12, Dz1 is the designation for a three-phase ...
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70
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Transformer load
I have 50 kVA delta-wye transformer with 3 single phases secondary (line-neutral) delivered to 3 houses, So if one of the 3 houses drown more power would that affect another 2 houses, or each phase ...
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1
answer
185
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May I get 220v phase-neutral if all the homes in my state seems to give only 127v phase-neutral voltage on sockets? [closed]
In my state (São Paulo, Brazil), theres delta-star transformers that outputs 4-wires. Three phase and one neutral.
I've heard that one of these wires of the triphasic (R,S,T wires) and the neutral ...
- 395
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1
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783
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Problem with plotting of 3-phase model in LTspice
I'm trying to simulate a model of a 3-phase transformer in LTspice.
My first attempt with different K values worked, but it didn't include the core saturation.
Now I tried to built a new model with ...
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155
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Balanced and unbalanced short circuit voltage of transformer
This might be trivial, but I'd like some hint on where to start.
I'm calculating power flow for three-phase-four-wire distribution networks. Positive sequence and zero sequence short circuit voltages ...
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3
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1k
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Is it possible to model a single-phase phase-shifting transformer in LTspice/Multisim/PSpice?
As you know, three-phase two-winding transformers can produce a phase-shift between the line-to-line or line-to-neutral phasor voltages of one side and the respective line-to-line or line-to-neutral ...
- 1,019
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178
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Using three-phase transformer in reverse
I'm in the US and installing a 45 kVA 480 V/208 V transformer in reverse, to power an electric car charger that requires 480 V. The secondary of the transformer is in wye configuration and I will be ...
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119
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3rd harmonic component of flux and current in Star -Star connected 3phase transformer
I wanted to understand what will be 3rd harmonic component of flux and current in following connection .
Connection -
Star- Star connection (with neutral on primary side only)
Further description-
...
- 1,204
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52
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Open-Delta 3-phase transformer kVA rating
I have a V-V three-phase transformer supplying a 50kVA balanced three-phase load. I know that the apparent power of a three-phase transformer \$S_{3\phi} = 3VI^*\$ and that of an open-delta system is \...
- 413
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3k
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3 phase transformer efficiency calculation
This is an assignment. No matter how hard I try the answer is never what I expect. Here is the question:
Three single phase transformers, each rated at 12 kVA, 120/240V, 60Hz, are connected to form a ...
- 113
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4
answers
110
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Phase and voltage conversion
I have a hypothetical question in regards to phase conversion and transformers, more specifically on their combination. I am not a certified electrician or engineer, so I don't know what all goes into ...
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1
answer
91
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DC unregulated power supply
I want to make a 70 VDC power supply, output unregulated with +/- 10V variation allowed.
I also want 50 A current from it.
My input can be 3-phase 380 V mains supply.
I cannot think of a 3-phase ...
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2
answers
112
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What does this symbol mean? And I have some basic problems which the book didn't mention
A power system book asked me this question, but honestly I don't understand the circuit of question and the solution which author provided.
Question:
There are 3 primary currents, \$I_R,I_S\$,and \...
- 551
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2
answers
118
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Step down 3 phase 2kV AC to 3-12V at modest current (5-20mA max)
I'm looking for a way to step down 3 phase, 2kV AC power to 3-12V DC. I do not have a neutral, just the 3 phases and ground. This will be entirely isolated, nobody will be anywhere near this thing. ...
- 3,521
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2
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185
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Will this 3-phase 208Y/120 setup work [closed]
OKAY...electrician I had out recommended the following setup to supply 3-phase wye 208/120v off of 240V single-phase. My device is pulling 30 amps, and my entire load is about 15KVA. It's impossible ...
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4
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1
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"Black box" transformer: Y-Y, Y-Δ, or Δ-Δ connected?
As a preface, this is purely hypothetical. I know better than to use a transformer without knowing anything about it. I'm just trying to get an idea of whether this is possible, not whether it's a ...
- 38.5k
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1
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3 phase transformer problem
We were given the following problem. We spent a night but could not even get close to solve it. It would be great if you could help us solve it.
Three identical 10 kVA, 19920/220 transformers are ...
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1
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538
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Delta wye transformer, voltages explanation?
So I'm doing a delta wye transformer simulation in simulink, and I need some
clarification about transformer voltages.
Here's a image from a youtube video
We have phase voltages on primary that ...
user226621
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2
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5k
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How to find phase shift(angle) between two signals in simulink?
So I'm doing a delta wye transformer in simulink and phase shift between these two signals should be 30 degrees, but how to show that, or calculate it? And how to find angle of each signal?
user226621
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2
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749
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How to show that voltages on diagram are 120° apart?
So i'm doing a matlab simulation of delta wye transformer and would need to show the phase shift between voltages. Here is a picture of input voltages so how would I show on this graph mathematically ...
user226621
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264
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Wye to delta 3 phase
Can someone please explain to me the following. For the last part, why did they use the Van to find Vab( secondary line voltage of the delta).
I did it and my magnitude matches the solution but the ...
- 41
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104
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Which capacitor in series with resistor circuit to reduce remanence effects of transformer?
The "Comparative Analysis of Mitigation Techniques for Inrush Current of Transformer" mentions "Pre-insertions resistor with capacitor method" as an inrush mitigation technique:
When circuit ...
- 709
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1
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1k
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Does using only 2 phases (400V) in a 3 phase transformer affect anything?
I just witnessed a 3 phase control transformer in the mcc that steps down 400V to 230V connected only with 2 phases on the 3 400V terminals, and on the other side (secondary) are your live and neutral ...
- 347
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129
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Why are all my motors and transformers failing at this specific location?
At my job there is a vacuum oven.
There is a 50 hp, enclosed cooling fan. that circulates N2 gas upon quench, the design of the unit runs 480 volts through a reduction transformer to 230 volts. This ...
- 111
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1
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2k
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Transformer Sizing with Mixed Loads (Three-Phase & Single-Phase)
I am trying to size/validate the rating on the medium voltage main transformer for an industrial plant. For some reason I can't find many resources that indicate how to properly do this when you have ...
user199402